Morning Blood Pressure Surge, Dipping, and Risk of Coronary Events

Original Article

Morning Blood Pressure Surge, Dipping, and Risk of Coronary Events in Elderly Treated Hypertensive Patients Sante D. Pierdomenico,1,2 Anna M. Pierdomenico,2 Roberta Di Tommaso,1 Francesca Coccina,1 Silvio Di Carlo,1 Ettore Porreca,1,2 and Franco Cuccurullo1,2 BACKGROUND The independent prognostic significance of morning surge (MS) of blood pressure (BP) is not yet clear. We investigated the association between MS of systolic BP and risk of coronary events in elderly treated hypertensive patients. METHODS The occurrence of coronary events was evaluated in 1,191 elderly treated hypertensive patients (age range 60–90 years). Subjects were divided according to tertiles of MS of systolic BP of the population as a whole, by dipping status and by group-specific tertiles of MS of systolic BP in dippers and nondippers. RESULTS During the follow-up (9.1 ± 4.9 years, range 0.4–20 years), 120 coronary events occurred. In the population as a whole, coronary event risk was not significantly associated with tertiles of MS of systolic BP, whereas nondippers were at higher risk than dippers. When nondippers and

dippers were analyzed separately, by group-specific tertiles of MS of systolic BP, coronary event risk was associated with MS of systolic BP in dippers but not in nondippers. After adjustment for various covariates, Cox regression analysis showed that dippers in the third tertile (>23 mm Hg) of MS of systolic BP (hazard ratio 1.912, 95% confidence interval 1.048–3.488, P = 0.03) and nondippers (hazard ratio 1.739, 95% confidence interval 1.074–2.815, P = 0.02) were at higher coronary event risk than dippers with MS of systolic BP 17.4 mm Hg) and dipping status (nondippers and dippers). Then, we analyzed nondippers according to groupspecific tertiles of MS of systolic BP (≤2.5 mm Hg; >2.5 and ≤11.5 mm Hg; >11.5 mm Hg) and dippers according to group-specific tertiles of MS of systolic BP (≤14.5 mm Hg; >14.5 and ≤23 mm Hg; >23 mm Hg) separately. Echocardiography

Measurements of interventricular septal thickness, left ventricular (LV) internal diameter, and posterior wall thickness were made according to standardized methods, within 1 month from clinic visit. LV mass was calculated using the formula introduced by Devereux et al.24 Individual values for LV mass were indexed by height2.7 and LV hypertrophy was defined as LV mass/height2.7 >50 g/m2.7 in men and >47 g/ m2.7 in women.25 Follow-up

Subjects were followed-up in our hospital outpatient clinic or by their family doctors. The occurrence of cardiovascular events was recorded during follow-up visits or by telephone interview of the patient followed by a clinical visit. Data were collected by the authors of this study. Those reviewing the endpoints were blinded to MS of systolic BP data. In the present report, we focused on coronary events that included fatal myocardial infarction, sudden death, nonfatal myocardial infarction, and coronary revascularization. Myocardial infarction was defined according to current criteria in various periods.26–28 Statistical analysis

Standard descriptive statistics were used. Groups were compared by using one-way analyses of variance and unpaired t-test, where appropriate. Bivariate correlation was used when needed. Event rates are expressed as the number of events per 100 patient-years based on the ratio of the observed number of events to the total number of patientyears of exposure up to the terminating event or censor. Survival curves were estimated using the Kaplan–Meier product-limit method and compared by the Mantel (logrank) test. Cox regression analysis was used to evaluate univariate and multivariate association of factors with outcome. First, univariate association between various variables and coronary events was evaluated. Then, multiple regression analysis was performed reporting in the final model variables that were significantly (P